Railway traffic controlling apparatus



' Sept. 8, 1936. WALLACE 2,053,884

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed March 12,1952 2 Sheets-Sheet 1 A INVENTOR. Wa/lade By QR H 4 ATTORNEY Sept. 8, 1936. H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed March 12, 1952 2 Sheets-Sheet 2 2. W a. m M 0 V T m M wz/ Q Patented Sept. 8, 1936 UNITED STATES RAILWAY TRAFFIC CONTROLLING APPARATUS Herbert A. Wallace, Edgewood, Pa., assignor to The Union Switch & Signal Company,

Swissvale, Pa., a corporation of Pennsylvania Application March 12,

9 Claims.

My invention relates to railway traffic controlling apparatus, and particularly to train governing apparatus adapted to be controlled from a remote point such as a train despatchers ofiice.

More specifically, my invention relates to the trackway portion of such apparatus.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2, when placed side by side, With Fig. 1 on the left, form a diagrammatic View illustrating a stretch of railway track containing a siding, with the associated trackway apparatus, embodying my invention, for giving the despatcher full control of traflic moving in either direction over the stretch of track containing the siding, without the necessity for wayside signals.

Similar reference characters refer to similar parts in each of the two figures.

Referring to the drawings, the stretch of railway track is divided into sections B-C, C--F, and F-G, each provided with the usual track circuit comprising a source of current 2 and a track relay designated by the reference character It with an appropriate exponent. Although I have shown source 2 as a battery, it will be understood that an alternating current source can be used instead, provided that the track circuits are suitably modified. In addition, I have provided a track transformer at each end of every section for at times supplying the track with alternating current which is periodically interrupted or varied at different rates or frequencies by a coding device, for the purpose of governing cab signals carried on a locomotive. For example, in section B-C, battery 2 which is connected in series with the secondary of transformer T supplies energy to track relay R Transformer T is arranged to supply periodically varied alternating current to the track rails of section B-C for controlling. trafiic moving in the direction from B to C, whereas transformer T is arranged to sup-ply periodically varied alternating 45 current to the same rails for controlling trafiic moving in the reverse direction. The alternating current which is periodically interrupted or varied to govern the cab signal indications may be of any suitable frequency, such as 60 or 100 cycles per second, for example.

The transformers in any given section are energized, at times, by a despatcher at ofiice Y, so that when a locomotive enters a given section, traific conditions being proper, alternating our- 5 rent periodically varied at a given frequency will 1932, Serial No. 598,434

be fed to the rails from the transformer at the exit end of that section. The locomotive-carried apparatus for translating this periodically varied rail current into cab signal indications, as well as the coding device for periodically varying the -5- alternating current, will not be described in detail as these form no part of my present invention. One form of such translating apparatus and coding device is shown and described in United States Patent No. 1,773,472 granted to 10 Paul N. Bossart on August 19, 1930, for Railway trafiic controlling apparatus.

Associated with track section C-F is a siding DE into which trains may enter over either of the manually operable railway switches WC or 15 WP. It is not necessary to provide a track hattery and a track relay for the siding D--E, but l have, however, provided transformers T and T for the purpose of supplying periodically varied alternating current to the siding rails 20 under certain conditions to be explained hereinafter. v

At the ends of track section 0-1, I have shown phantom signals S S S and S- It is to be understood that in my invention I specifically 25 contemplate that no wayside signals need be used, and I have shown the above phantom signals merely to make it easier to visualize the cab signal indications in the various sections.

Wherever, throughout the following descrip- 30 tion, the display of signals is mentioned, it will be understood, therefore, that reference is made to cab signals and not to wayside signals.

It will be understoodthat the cab signal indication represented by signal S will be received 35 throughout approach section 3-0 by a train moving from left to right. Likewise, the indication represented by signal S will be received throughout main section FC by a train moving from right to left. The indications of the remaining 40 signals illustrated are effective in a similar manner in the respective sections governed thereby.

For purposes of illustration, I shall make use of code frequencies 180, 120, and 80 interruptions or periodic variations per minute in the alternat ing current supplied to the rails by coding devices such as NC or NF, for producing cab signal indications corresponding to the frequency of such periodic variations. I shall use the code frequency of 180 to indicate proceed; the code frequency of will indicate approach; whereas the code frequency of will indicate take siding in the case of a train entering section 13-4) or G-F, and the same code'frequency of 120 will be interpreted to mean leave siding whenre- 55 ceived by a train occupying siding DE. The absence of code will result in a stop indication.

It will be understood that the above code frequencies, as well as the number of codes used, are merely illustrative, and other code frequencies can readily be used, and the number of codes changed to provide different or additional information by which the train may be governed, the purpose of the present disclosure being to show only the essential elements of a simple operative system in order not to complicate the disclosure unnecessarily.

I propose to give the despatcher direct control of those signal indications which govern trafiic movements in the proximity of stations such as C and F. It will be apparent without further explanation that the despatcher can be given control of signal indications at any additional locations, for conveying any desired information to a train by merely duplicating some of the control apparatus, herein disclosed.

For controlling the signal indications which govern traflic in the vicinity of the left hand end of section CF, I have provided a group of four stick relays MC, SC, RC and LC, and a similar group comprising stick relays RF, LF, SF, and MF, is provided for governing trafiic in the vicinity of the right hand end of section C--F. The relays of either group can be energized either singly or in appropriate pairs by 'means of suitable code impulses originating in the despatchers oflice Y, containing the despatchers code transmitter, and transmitted therefrom over the line circuitD D These code impulses originating in the despatchers office are not to be confused with the alternating current code frequencies which are impressed on the track rails, and which originate in the coding devices NC and NF.

Relay MC or MF, when energized, selects a main line route by causing appropriate cab signal indications to be displayed in the approach track section BC or GF,.respectively, whereas relay SC or SF selects a route over the siding DE. Relays RC and LC, as well as RF and LF are traflic direction relays and determine whether trafllc is to move in the right hand or the left hand direction, respectively. The manner in which the above stick relay groups govern the cab signal indications will be explained hereinafter.

Each of the above stick relay groups is controlled by a group of decoding relays designated by the reference characters QC and QF, having the function of closing a pickup circuit, or opening a stick circuit, for one or more stick relays of the first group upon receipt of the proper code over the line wires D and D The decoding groups QC and QF, as well as the code transmitting apparatus at the despatchers office, are not shown in details, as such apparatus is well known in the art, and any one of several systems'can be used, as for example, the system shown and described in the copending application for Letters Patent of the United States, Serial No. 373,675, filed by Lloyd V. Lewis, on June 25, 1929, for Remote Controlling Apparatus. For the'purpose of my present invention, it will be sufi'icient to state that, upon the transmission of a suitable code from the despatchers oifice, proper cab signalcontrolling devices will be actuated at any one of several possible wayside or field stations, such as station C or station F.

, Both track switches WC and WF are shown occupying the normal position, for main line traffic movement, and the corresponding switchoperated circuit controllers VC and VF are also in the normal position, in which contacts 45 and l8 are closed. As soon as either switch is moved a short distance away from the normal position, contacts 45 and 1--8 both open. When the switch reaches its reverse position, contacts 4-8 close, but contacts 7-8 remain open. The track circuit for section CF includes the contacts 78 of each circuit controller VC and VF. It will be apparent, therefore, that if switch WF is reversed, the rail circuit of section CF will be opened and a train approaching switch WF from the left on section CF will receive a stop indication. A similar condition will exist in the case of a train moving in the reverse direction and approaching switch WC from the right on section CF, if switch WC is reversed.

Relays KC and KF are slow acting alternating current relays capable of remaining steadily picked up when supplied with the periodically carried alternating current which is fed to the track transformers for producing cab signal indications. The releasing time of relay KC or KF is sufficiently long to prevent closing of back contact 9 or opening front contacts 33 and 41 during the recurring intervals when the value of the periodically interrupted or varied alternating current is a minimum or zero.

The purpose served by stick relays JC and JF, and repeater relays PC and PF, will become apparent from a description of typical traffic movements to be presented in detail hereinafter.

For simplicity, I shall assume that coding devices NC and NF operate continuously, supplying periodically varied alternating current of code frequencies of 180, 120 and 80 variations per minute to wires I80, I 26 and 80, respectively. It will be understood, however, that these coding devices can be arranged to be normally deenergized, being set into operation by the approach of a train, in the usual and well known manner.

With the above preliminary explanation in mind, I shall assume that a train approaching from left to right has entered section B-C, and that the despatcher wishes to instruct the train to proceed on the main line, section CF being unoccupied. To do this, the despatcher will send out a suitable code over wires D and D which will pick up the main route stick relay MC and the right hand traflic direction stick relay RC, at station C. Transformer T will now receive current of 180 code frequency over a circuit starting at wire I80 of coding device NC, wires H and I2, front contact l3 of relay PC, wire l4, front contact l of relay MC, wire l6, front contact [1 of relay RC, back contact l8 of relay LC, wire l9, and primary winding of transformer T to common terminal 0. Track section BC will therefore be provided with current of 180 code frequency and the cab signal of the train will indicate proceed at full speed, which will mean proceed on main line.

If, instead of instructing the train to proceed on the main line, the despatcher wishes to have the train enter the siding D-E, he will send out a suitable code to pick up siding route stick relay SC and right hand trafiic direction stick relay RC. Transformer T and therefore track section BC, under this condition, will receive current of 120 code frequency over a circuit starting at wire I20 of coder NC, wire 20, front contact 21 of relay SC, wire l6, front contact I! of relay RC, back contact I 8 of relay LC, and wire l9 to trans former T as before. The cab signal will now indicate take siding? through track section B-C,

foratrain movement into siding:DE. The distance B-C should, of. course, be. adequatefor permitting the train to come to .a stop at. point C.

In a similar manner, the despatcher may, at will, impress current of 80 code frequency upon track circuit B-C to cause an approach cab signal to be displayed, by sending out a code to pick up either one or the other of stick relays MC or SC, keeping the three remaining stick relays at station C deenergized. The circuit for transformer T with relay MC picked up, will start at wire 80 of coder NC, wires 22 and 23, front. contact 24 of relay MC, wires 25 and 25', back contact I! of relay RC, back contact l8 of relay LC and wire 19 to transformer T If relay SC had been picked up instead, the above circuit for transformer T would include wire 13 and front contact 14 of relay SC, in place of wire 23 and front contact 24 of relay'MC.

If the despatcher' wishes to display a stop signal in section B-C, he may do this by sending out a code which will release any stick relays remaining energized at station C, whereupon the circuit for transformer T will be opened and no code current will be fed to track circuit B-C, resulting in a stop indication.

It will be understood that the pick-up circuits for stick relays RC and LC, governed by the decoding relays QC, are so arranged that it is not possible for both relays RC and LC to be picked up at the same time, this requirement being essential since these relays govern opposing traffic routes. For a similar reason, stick relays MC and SC cannot both be energized at one time. Once a route is set up by picking up the proper stick relays at station C, the stick feature of these relays will cause this routeto be maintained for following trains without further action by the despatcher, until the despatcher sends out a deenergizing code, or until he sends out a code to set up a route inconsistent with the route then effective.

I shall now describe the manner in which traffic moving toward section B-C from the left, or toward section GF from the right, is controlled, and this can be illustrated to best advantage by rearranging the two sheets. of. the drawings so that Fig. 2 occupies a position to the left of Fig. 1. When arranged in this manner, the drawings illustrate. an extension of the system through the single track stretch between control points such as F and C. If track section B-'C is unoccupied; and relay'LC is deenergiz-ed, a train moving from left to right will receive a proceed signal in section G-B because transformer T will be energized with current of 180 code frequency by virtue of a circuit starting at wire Hi5 of coder NC, wires H and 21, back contact 23 of relay LC, wire 29, front contact 39' of track relay R and wire 35 to transformer-T Similarly; if track sections B-C and GB are both unoccupied, a train movingv from left to' right in section F-G will receive a proceed' signal, provided" the dispatcher has caused relay RF to be energized to establish the corresponding direction of traflic; The proceed signal in section F-Gr will be obtained because transformer T will be energized with current of 180 code frequency by virtue of the same circuit just traced. for transformer. T and which includes, in addition, wire 63-, front contact 64' of relay R wires 65 and 66, transformer T wire 61, and front contact 68 of relay JF to terminal 0. Relay JF will have become: energized-because when the: train entered section: F-G, it caused the. release of track relay R*, which resulted inthe release of relay KF, causing a pickup circuit for relay JF to become closed over back contact 9 of: relay KF and front contact 55 of right hand traffic direction relay RF.

Traffic approaching. section GF from right to left will be governed in an analogous manner by transformers T and T which are energized over: back contact 28 of relay RF, and front contacts of track relays for the intervening track sections. Likewise, a train in section G-F, approaching switch WF, will be governed by coded current supplied to transformer T the codefrequency of this current being usually determined by the condition of the four stick relays MF, SF, LF, and RF at station F, under the control of the despatcher.

It may be noted that a train entering section FG from the left, or entering section BC from the right, will have its supply of code frequency current cut off from the time it enters the section until relay JF or J0 picks up. This however is without effect upon the operation of the system, for the reason that the vehiclecarried apparatus for controlling the cab signals is preferably made sufficiently slow acting to bridge such gaps in. the trackway control as may occur when a train moves from one block to another, in order to avoid unnecessary breaks in the continuity of the cab signal indications.

Returning the drawings to the original position, with Fig. 1 on the left, assume that a train moving from leftto right and occupying section B-C has received a proceed signal. This train will enter the main line of section CF, and if relays MF and RF at station F are energized; current of I80 code frequency will be supplied to transformer T and therefore. to track section CF, so that 2. proceed cab signal will result. The circuit for transformer T will be from wire H30 of coder NF, wire 32, front contact 33 of relay KF, wire 54, front contact 35 of relay MF, wire 36, front contact 3'! of relay RF, back contact 38 of relay LF, wire 39, and contact 5-4 of controller VF to transformer T Relay KF repeats front contact 40. of track relay R as well as the front contacts of track relays to the right of point G, and front contact 33 of relay KF therefore insures that a proceed code will notbe supplied to transformer T if section F-G, or a section to the right of point G, is occupied. Should one of such sections be occupied, the resulting deenergization of relay KF will cause an approach code to. be supplied to transformer T overback contact 33 of relay KF and wires M and 80.

If a train is occupying section CF and the despatcher inadvertently attempts to supply proceed code to transformer T by picking up relays MC and RC to permit a following train in section B-C to enter the main line, transformer T will be incapable of receiving a proceed code, and will receive an approach code instead. This will result because track relay R being 'deenergized under this condition, will deenergize relay PC at front contact 42, and 80 code will be furnished to transformer T over a circuit from wire 8?} of coder NC, wires 22, 43, and 44, back contact 13 of relayPC, wire 14, front contact l5 of relay MC, wire i6, front contact I! of relay RC, back contact is of relay LC, and wire E9 to transformer T 1 The approach code will also be effective at transformer T even though section 0-]? is unoccupied, should the despatcher, prior to attempting to supply the proceed code to transformer T have permitted left hand traffic relay LF to remain energized. The circuit for relay PC would now be interrupted at back contact 45 of relay LF, and the back contact l3 of relay PC would now impress code, as before, independently of the condition of track relay R If, after a train moving from left to right has entered the main section 0-35, the despatcher wishes to hold the train on the main line, as he might wish to do to permit an opposing train to enter siding E-D, he will release relay MF, whereupon, no energizing circuit will exist for transformer T because front contact 35 of relay MF will be open, and the train will not receive any code, resulting in a stop signal for the main line train. If the despatcher wishes to instruct a train moving on the main line to stop at the right hand end of section CF, he may display an approach signal in this section by energizing either one of the relays IVLF or SF, maintaining both relays RF and LF deenergized. The circuit for transformer T will now be from wire 80 of coder NF, wire 22, wire 23 and front contact 24 of relay MF, (or wire 73 and front contact '14 of relay SF, if relay SF is picked up instead. of relay NF) wires 25 and 75, back contact 3'! of relay RF, back contact 38 of relay LF, and wire 39 to transformer T Assume now that after a train has entered the siding DE, as a result of code supplied to transformer T the despatcher wishes to instruct the train to leave siding. To do this, he will send out a code to pick up relays RF and SF, whereupon, transformer T will be supplied with 120 code, which, when received by a train occupying the siding will be interpreted to mean leave siding. The circuit for transformer '1 starts at wire I20 of coder NF, wire 46, front contact 4'! of relay KF, wire 48, front contact 49 of relay SF, wire 50, back contact 54 of relay LF, front contact 52 of relay RF, and wire 53 to transformer T If the despatcher wishes to hold the train on siding D-E, he wiil fail to pick up relays RF and SF, so that transformer T will not receive current, resulting in a stop indication. Transformer T serves a similar purpose with respect to a train which entered siding DE from the right.

Because of the shunting effect of the wheels and axles of a locomotive, the code receiving equipment on a locomotive must be placed forward of the first pair of Wheels, and this equipment is therefore responsive only to coded current supplied to the rails ahead of the locomotive. For this reason, it is necessary to furnish a codesupplying transformer at each end of a track section, in order that the cab signals will be operative for either direction of traffic movement.

When switch WF is reversed to permit a train to leave siding D-E, contact 6-4 of controlled VF becomes closedso that the leave siding code being furnished to transformer T will also be supplied to transformer T to continue the leave siding indication until the train enters section F-G. At the same time, contact 8'! of controller VF becomes open, opening the main line rail circuit of section .C-F, to prevent a train, which might be approaching from the left on section C-F, from picking up the 120 code, and receiving the corresponding signal indication. The opening of contact 5-4 of controller VF, which disconnects transformer T from wire 39 when switch WF is reversed, insures that under no condition can a train in section C-F, approaching from the left, receive a proceed code with switch WF reversed.

To explain the manner in which a train is governed after leaving section CF, either from the main line or the siding, I shall assume that the train has entered section FG, deenergizing track relay R Front contact 40 of relay R will be open, and will deenergize relay KF. To permit the train to enter section FG, it was first necessary for relay KF and also relays MF and RF, or SF and RF to have been energized, according as the train approached from the main line, or the siding. In either case, relay RF is picked up, so that when relay KF releases, a pick-up circuit for relay JF becomes closed. This circuit may be traced from one terminal U of a source, back contact 9 of relay KF, wires [0 and 54, front contact 55 of relay RF, wires 56 and 51, and winding of relay JF to the other terminal V of the source. As soon as relay JF picks up, a stick circuit becomes closed over wire 58 and front contact 59, so that relay JF will remain energized as long as relay KF remains released, even though relay RF becomes deenergized in the meantime. If now the drawings are again rearranged so that Fig. 2 occupies a position to the left of Fig. 1, it will be seen that transformer T will now receive code over a circuit starting at a coding device NC, Fig. 1, wires II and 27, back contact 28 of relay LC, wire 29, front contact 38 of relay R wire 63, front contact 64 of track relay R wires 65 and 66, transformer T wire 57, and front contact 68 of relay JF to the other terminal 0 of the code source. The code frequency will be supplied to transformer '1 provided sections GB and 13-0 in advance are unoccupied, and relay LC at the next station to the right of T is deenergized.

It will be clear from the foregoing that the despatcher must pick up relay RF in order to provide a proceed signal for a train leaving station F and occupying section FG, but that as soon as the train enters section FG and accepts this signal, the cab signal is removed from control by the despatchers apparatus at station F and that relay RF may be released without interfering with the cab signal of the departing train.

Assume now that a train is approaching station F from the left and the despatcher wishes to prevent the train from passing point F. As previously explained, the despatcher may energize relay MF or SF only, whereupon a train on the main line would receive an approach signal, which would be interpreted to mean stop at station F, while a train on the siding would receive a stop signal. Furthermore, the despatcher may deenergize all stick relays at station F, whereupon a train on the main line would receive a stop signal. If, under any of these three conditions, the train should fail to stop before passing point F, even if wire 63 were supplied with 180 code and relay RH were energized, the released condition of relay JF would cause a stop signal to be displayed in section FG, as a further precaution for holding the train. In the absence of a relay such as JF, track transformer 'I would repeat only the traffic conditions ahead, and an engineman ignoring or overlooking the stop indication of signal S would receive a proceed signal in section F-G, obviously against the wishes of the despatcher.

Although I have shown means for repeating the stop indication into but one section in ad- Vance, which I consider to be suificient, it will be apparent that such indication could be repeated into several sections, in similar manner. Also, a stop indication in either of the sections G-F or B-C could be repeated into section C-F, for added safety, by similar use of the stick relays JF or JG, directionally selected over the directional relays LP or RC, respectively.

Although I have described certain traffic movements in a given direction only, it will be apparent without further explanation, from the similarity of the control apparatus at stations and F, that analogous traffic movements in the reverse direction can be similarly controlled.

To summarize briefly, I have provided a system of railway traiiic control in which cab si nals on a locomotive can be controlled at the will of a despatcher located at some distant point, for the purpose of eliminating wayside signals} and facilitating traflic movements. I accomplish this result by making use of rail current periodically varied at diiferent frequencies, which frequencies are under the direct control of a despatcher, for controlling traffic movements in accordance with the will of the despatcher, while retaining the safety features necessary for the protection of following and opposing train movements. That is, although track conditions might be such as to make it safe for a train to proceed, the despatcher may display a cab signal indicating that the train should stop, take siding, or proceed on main line. However, if track conditions are such as to make it unsafe for a train to proceed, restrictive signals will be displayed, irrespective of action taken by the despatcher.

Although I have made use of cab signals in illustrating only one embodiment of my invention, it will be understood that my invention can be applied to the control of train governing means of any suitable type. It will be understood also, that although I have described apparatus for controlling but three code frequencies supplied to the trackway, my invention is not limited to the control of this number of codes or to the use of rail current varied in this particular manner, but that the equipment can be expanded to control additional code frequencies, or adapted to control rail current varied in any suitable manner, for performing suitable governing functions upon a train, or supplying any desired information thereto.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of track including a railway switch, means for supplying the track rails of portions of said stretch with varying current of different characteristics to govern traffic movements over said switch in different directions and routes in accordance with said characteristics, a pair of route stick relays and a pair of traffic direction stick relays, means governed by said relays for controlling the characteristics of said current in accordance with the selective operation of one relay of each of said pairs, and a manually governed device for selectively operating one relay of each of said pairs.

2. Railway traffic controlling apparatus comprising a line circuit connecting a despatchers office with two remote stations each located at one end of a main track section havin a Sid.- ing associated therewith, an approach section adjacent each end of said main section, means for supplying the track rails of each approach section with alternating current periodically val-,- ried at different frequencies for, controlling traf-y fic movements into said main section or said siding in accordance with said frequencies, means each of said stations controlled from the d 35- patchers ofiice over said line circuit for controlling said frequencies, and means effective when current of a given frequency is being, supplied to one of said approach sections for pre-, venting current of the same frequency from being simultaneously supplied to the other approach section.

3. In combination, a stretch of railway track divided into track sections, means for supplying alternating current periodically varied at different frequencies to the track rails of one section. as well as to an adjoining section for controlling traffic movements in said two sections 11 313091111 ance with said frequencies, a manually operable device for at times controlling the frequency of said periodic variations and for at other times discontinuing the supply of current to said one section, and means governed by trafiic moving from said one section into said adjoining section when the current in said one section has been discontinued for preventing the supply of current to said adjoining section.

4. In combination, a dispatchers office and a remote station connected by a line circuit, a stretch of railway track comprising two sections extending in opposite directions from said station, selecting means at said station for supplying current of a selected one of a plurality of possible characters to the track rails of one section or the other, said selecting means including means for selecting the character of current and direction selecting means for determining to which of the two sections the current of selected character is to be supplied, and means controlled from the dispatchers office over said line circuit for controlling said selecting means.

5. In combination, a dispatchers ofiice and a remote station connected by a line circuit, a stretch of railway track comprising two sections extending in opposite directions from said station, selecting means at said station comprising direction selecting means for selectively supplying current to the track rails of one section or the other to govern the indications of a cab signal on a vehicle in the selected section approaching said station, and other selecting means for selectively governing the current supplied to the track rails to determine which one of a plurality of possible indications will be displayed on said vehicle, and means controlled from the dispatchers office over said line circuit for controlling said selecting means.

6. In combination, a dispatchers ofiice and a remote station connected by a line circuit, a stretch of railway track including two sections extending in opposite directions from said station, a plurality of sources of current at said station, selecting means for connecting a selected one of said sources to the track rails of one of said sections or the other for controlling the movement of traffic approaching said station from one direction or the other in said stretch, and means controlled from the dispatchers office over said line circuit for controlling said selecting means.

7. In combination, a dispatchers office and a remote station connected by a line circuit, a stretch of railway track adjacent said station, a stick relay effective when energized to supply current to the track rails at one end of said section to govern the indications of a cab signal on a vehicle occupying said section, a pickup circuit for energizing said relay including a contact controlled from said dispatchers oflice over said line circuit, and a stick circuit for said relay including its own front contact and a contact closed when said section is occupied by a vehicle.

8, In combination, a dispatchers ofiice and a remote station connected by a line circuit, a stretch of railway track including a first and a second track section adjacent said station, selecting means at said station for at times supplying train governing current to the track rails of said sections, means controlled from the dispatchers oifice over said line circuit for controlling said selecting means, and means governed by traffic moving from said first section to said second section for maintaining the supply of train governing current to the track rails of said second section irrespective of the condition of said selecting means.

9. Railway traific controlling apparatus comprising a line circuit connecting a dispatchers ofiice with a plurality of remote stations including one at each end of a section of railway track, a track circuit for said section including a battery connected across the track rails at one end and a track relay connected across the track rails at the other end of said section, a track transformer at one station having its secondary winding in series with said battery, a track transformer at the other station having its secondary winding in multiple with said relay, selecting means at each station controlled from the dispatchers oifice over said line circuit, means controlled by each said selecting means for at times supplying alternating current to the primary of the transformer at said station to control the movement of trafiic in said section, and means controlled by said track relay for controlling the movement of traffic approaching within a predetermined distance of said section.

HERBERT A. WALLACE. 

